Characterizing seeds of tropical weeds is crucial for future research to understand their ability to disperse in space and time through their seeds, and building up seed banks. Seeds of 55 weed species occurring on Reunion Island were collected and characterized. Seeds were described by their shape, size, color, texture, hairiness, or particular markings. Seed traits were recorded in a database in French and English. It has been published on the CIRAD AMATROP dataverse, which centralizes datasets on tropical weeds. It will be updated as new weed seeds from tropical regions are characterized. In a long-term perspective, these data allow for creating a multicriteria identification key to identify seeds to study seed stocks in agricultural fields.